首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3136404篇
  免费   267526篇
  国内免费   13883篇
耳鼻咽喉   43507篇
儿科学   96367篇
妇产科学   80978篇
基础医学   504709篇
口腔科学   86182篇
临床医学   279780篇
内科学   543254篇
皮肤病学   84842篇
神经病学   271822篇
特种医学   125186篇
外国民族医学   196篇
外科学   492534篇
综合类   101250篇
现状与发展   24篇
一般理论   2181篇
预防医学   265206篇
眼科学   71251篇
药学   215863篇
  22篇
中国医学   9111篇
肿瘤学   143548篇
  2021年   54528篇
  2020年   34774篇
  2019年   57653篇
  2018年   69924篇
  2017年   53256篇
  2016年   58782篇
  2015年   73212篇
  2014年   107278篇
  2013年   172266篇
  2012年   82959篇
  2011年   80884篇
  2010年   113212篇
  2009年   118837篇
  2008年   68194篇
  2007年   70407篇
  2006年   81591篇
  2005年   77272篇
  2004年   79809篇
  2003年   70995篇
  2002年   60637篇
  2001年   83960篇
  2000年   76111篇
  1999年   79966篇
  1998年   63060篇
  1997年   61523篇
  1996年   59263篇
  1995年   54808篇
  1994年   49144篇
  1993年   45971篇
  1992年   57329篇
  1991年   54587篇
  1990年   51792篇
  1989年   51374篇
  1988年   48157篇
  1987年   47066篇
  1986年   44872篇
  1985年   45466篇
  1984年   43533篇
  1983年   40208篇
  1982年   40251篇
  1981年   38093篇
  1980年   36020篇
  1979年   36866篇
  1978年   33504篇
  1977年   30827篇
  1976年   28034篇
  1975年   26556篇
  1974年   27675篇
  1973年   26592篇
  1972年   25028篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
14.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
15.
16.
17.
18.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号